The microbial world is diverse owing to its 3.7 billion years of evolution, which provides for both the[unreadable] opportunity of undiscovered metabolic capacity, including that for pollutant degradation, and the challenge of[unreadable] detecting and recovering this activity. It is well known that more than 99% of the microbial world has not[unreadable] been cultured and hence remains undiscovered. We propose to explore and recover genes for two key[unreadable] biodegradative steps in the detoxification of chlorinated polyaromatic compounds from the DNA of[unreadable] this uncultured microbial diversity, and then to use the molecular markers from this study to aid in[unreadable] site assessment and quantitative predictions of biodegradation at contaminated sites. We are[unreadable] targeting the reductive dehalogenases and the aromatic oxygenases as the key functions to recover since[unreadable] they are most often the rate limiting steps in the degradation of the polychlorinated dioxins and[unreadable] dibenzofurans, PCBs and polynuclear aromatic hydrocarbons (PAHs), the Superfund chemicals of focus in[unreadable] our study. Our specific aims are to: (1) explore and recover nature's catalytic diversity with the goal of[unreadable] developing a comprehensive profile of microbial metabolic capabilities for these polyaromatic compounds,[unreadable] (2) use the genome sequence information of Burkholderia xenovorans LB400, the most effective PCB[unreadable] degrader, to study the metabolic features important to the degradation of these chemicals and (3), develop[unreadable] quantitative diagnostic tools based on Bayesian probabilistic networks to predict biodegradation at[unreadable] contaminated sites. We propose to use enrichments to help identify the functionally active populations and[unreadable] hence genes, to use stable isotope probing to recover DNA from the active degrading populations, to use[unreadable] metagenomic libraries to recover the full genes and operons, and to use high throughput PCR screening for[unreadable] identifying clones with the targeted gene families. This project combines the expertise of the Rutgers[unreadable] University scientists in aromatic oxygenases and high throughput screening and metagenomics with the[unreadable] expertise at Michigan State University in reductive dechlorination and genomics and microarray technology.